A slide-fastener stringer generally comprises a pair of stringer halves each formed with a support tape and, along an edge of this tape, with a row of coupling members, heads or links adapted to interdigitate with the heads or coupling members of the opposite stringer half upon movement of a slider therealong.
In the coupled state, each coupling member or head is received between a pair of coupling members or heads of the opposite row of coupling members, i.e. in an interhead space thereof, the head being generally provided with formations which lock one behind the other to prevent lateral forces, i.e. forces in the plane of the slide-fastener stringer, from causing separation of the stringer halves.
Of course, the coupling heads can have configurations intended to resist other types of stresses as well, i.e. forces perpendicular to the slide-fastener plane and torsional forces about the axis of the slide fastener.
Slide fasteners of this type can be made "separable", i.e. can be designed to permit at least one end and usually both ends of the slide fastener to separate from one another in the decoupled condition. Such slide fasteners are most common in garments, such as jackets, sweaters, coats, and have endstop members at this one end which can be locked together to permit the slider, upon movement from this end, to interdigitate the two rows of coupling members.
While linearly or arcuately insertable endstop members are most widely known and common, i.e. one endstop member is shifted generally along the slide-fastener axis into a channel or passage of the other endstop member and similarly into the channel or passage of the slider, it is also known to provide pivotable or swingable separable endstop members wherein one of the endstop members pivots upon the other and thus swings laterally into a laterally open channel of the slider. The present invention is primarily concerned with such swingable separable endstop members and, when reference is made hereinafter to the separability of the endstop members, it should be understood that it is this swingable type which is of concern.
In the conventional construction of swingable separable endstop members, one of these members is provided at one end with a pintle, pin, boss or other formation defining a pivot axis and receivable in a seat of the other endstop member to permit the relative swinging movement in the plane of the slide fastener. To ensure an effective locking of the two endstop members against the opposite pivotal movement which could lead to undesirable opening of the slide-fastener from this end after the slider has been moved away, complex locking elements are provided on the two members. These locking members which must be fabricated with high precision to interfit tightly are expensive, unreliable and prone to damage. Furthermore, it has been found, as a practical matter, to be difficult to interfit the locking elements and hence the two coupling members so that the manipulation of the slide-fastener is difficult and inconvenient.